If we have a simple external format for metadata, we can send a
document and its metadata together using multipart/related.
I think we should consider what it takes to make WEBDAV work over
email, e.g., where you MAIL an update to the web server as an
attachment.
If we're careful about data formats, this should work as well as using
HTTP. (This is an argument for tipping the balance toward 'new mime
types' rather than 'new method names' since mail really only has
POST).
Larry